Hitachi Industrial Equipment Systems Co., Ltd.

Hitachi, Ltd.

Hitachi Construction Machinery Co., Ltd.

Takeshi Obata

Tadahiro Shimozono

Kouji Obata

Koichiro Saito

Osamu Matsumoto

Hideaki Kobayashi

Kenichi Saito

Koji Obata

Takashi Yasuhara

Masami Ochiai

Takayuki Koizumi

Masaharu Senoo

Keiji Fukushi

Keiichiro Kaihatsu

Akihiro Sekine

Mituru Itou

Yoshiomi Jojima

Apparatus and method for partial discharge detection of turn-to-turn insulation in motor has a surge generator for generating a surge voltage to the windings of the motor by applying a pulse voltage, and a partial discharge current detector for detecting partial discharge currents between the winding turns of the motor. The surge generator generates in and between the windings of the motor the surge voltage that has the rise time and fall time corresponding to the rise time of the surge voltage observed at the motor terminal when the motor is driven by an inverter, and that is repeated at a frequency of 50 Hz to 20 kHz.

Apparatus and method for detecting partial discharge at turn-to-turn insulation in motor

In a rotary electric machine, for enhancing the reliability and reducing the size thereof, the rotary electric machine comprises a stator, and a rotor opposed to the stator and adapted to be rotated around a shaft, the rotor having an iron core formed therein with a plurality of axial holes formed in the iron core, a plurality of conductor bars inserted respectively in the holes, and end rings provided at the end parts of the conductor bars, wherein the outer peripheral parts of the end rings are electrically and mechanically joined to the conductor bars through friction stir welding, and the one end part of the conductor bar is axially projected from the end ring. With this configuration, it is possible to enhance the capability of heat radiation from the rotary electric machine and to enhance the design freedom of component parts around the stator and the rotor.

Rotary electric machine

A frequency converter for outputting a power to drive a motor, having: an inverter unit for inverting a d.c. power to an a.c. power; a control unit for controlling the inverter unit; and a housing for supporting at least the inverter unit and control unit, wherein a rise time change unit is provided in the housing, the rise time change unit changes a rise time of a waveform of a voltage output from the inverter unit.

Frequency converter, motor, motor drive system and maintenance method for motor drive system

A rotating electric machine includes a stator core of a cylindrical shape, a rotor core coaxially rotating inside the stator core, and a plurality of coils each formed by winding magnet wires using a slot formed axially in either the stator core or the rotor core, or both: it is preferable that each of the coils be split into a plurality of coil groups, that starting sections of winding of the magnet wires in one of the coil groups be wound adjacently to ending sections of winding of the magnet wires in another of the coil groups, and that the starting sections and ending sections of winding of the magnet wires in the two coil groups be connected at respective outgoing wire ends to one another, outside the slots.

Rotating electric machine, winding machine, and rotating electric machine system

A directly motor-driven spindle assembly in a rotary shaft having one end supported on a bearing and the other end connected to a load a, driving apparatus fixed to the rotary shaft to rotate the rotary shaft, and control apparatus for controlling the movement of the rotary shaft toward the side of the load according to the movement of the rotary shaft from a predetermined position. The control apparatus prevents the jumping motion of the rotary shaft which occurs as the load increases to enable the directly motor-driven spindle assembly to operate at a high rotating speed without the jumping motion.

Directly motor-driven spindle assembly

A spinning machine and method of control thereof wherein the spinning machine includes spindles for winding twistings or single yarns and including peripheral equipment for the spindles wherein the spindles and peripheral equipment are individually driven. A speed detector detects the rotation speed of at least one of the spindles and the peripheral machinery and a speed control arrangement is provided for controlling the speed of one of the spindles and the peripheral equipment in response to the detected speed so as to enable operation of the spindles and the peripheral machinery in a corresponding or synchronized manner. By the synchronized operation of the spindles and the peripheral machinery, yarns of excellent quality can be obtained.

Apparatus and method for control of a spinning machine

A ring spinning machine has a direct drive spindle rotatably supported by an upper bearing in a bolster and connected to a rotor of a spindle motor having an upper structure including upper coil end of a stator thereof. A ring is movable up and down along the spindle to guide a yarn to be wound on a bobbin carried by the spindle. The inside diameter of the ring is determined in relation to the size of the upper structure of the spindle motor such that the upper structure can be received at least partially in the ring when the ring is moved to the lower end of its vertical stroke. The length of the unsupported portion of the spindle is reduced to increase the critical or resonance speed of the spindle, thus enabling the spindle to operate at an increased speed.

Ring Spinning machine

A spindle apparatus for winding fibers has a spindle which is directly fixed to a rotor of an electric motor. One of a pair of magnetically-coupled thrusting members is fixed to a rotary part of the apparatus, while the other of the thrusting members is fixed to a stationary part of the apparatus, so that a downward thrusting force is applied to the spindle to prevent lift of the spindle during rotation thereof.

Growing community of inventors

Narashino, Japan

Takeshi Obata